A "rogue marker" is said to be behind the leaked answers to an English test due to be taken by 11-year-olds in the UK.

The answers to the Key Stage Two grammar, punctuation and spelling test, being taken today by pupils across England, appeared on a website for exam markers on Monday evening.

They stayed online in a password-protected area for several hours until the error was spotted and the answers removed.

The tests were not cancelled because the British department of education said there had only been a few dozen visitors logging on to the site.

British media reports that a department source said, "while the test doesn't appear to have leaked into the public domain and can go ahead, a rogue marker did attempt to leak the test's contents.

"It is clear there is now an active campaign by those people opposed to our reforms to undermine these tests and our attempts to raise standards."

It is the second time such an error has happened in just a few weeks - a spelling test for thousands of seven-year-olds had to be scrapped in April after being revealed online.

Earlier, a department spokesperson said: "We are aware that Pearson, the external marking supplier responsible for Key Stage Two tests, published the [...] grammar, punctuation and spelling test on its secure marker site, for a short period of time. We are urgently investigating this breach.

"Unlike the Key Stage 1 test, we have no evidence to suggest this was leaked into the public domain by the time schools began to administer it. The integrity of the test has not been compromised and schools should and must deliver it as planned.

"The site can only be accessed by Pearson's approved markers, all of whom are under secure contract. Any distribution of materials constitutes a clear breach of that contract."